Headlamp



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N 1. A. RITTER.

"f HEADLAMP.

APPLICATION FIL-EDLOCT. 2l, 1920.

1,393,573; Patented oct. 1i, 1921.

Ffa L f @Hoang narran stares PATENT FFHCE.

JOHN A. RITTER, or LaNsnovvNnI 1=ENNsYrfvf1N1.a.-

Specification of Letters Patent.

Application led etober-` 21, 1920. Serial No. 418,396.

'State of Pennsylvania, have invented certain neu/Land usefulImprovements in Headlampsand I herebyT declare that the following is afull, clear and exact description thereof, reference being hadto theaccompanying drawings, which form part of this specification. y

My invention relates particularly to head lamps on moving vehicles, suchas automobiles, railway locomotives, interurban electric cars and thelike, and it improves the art by providing means for reducing the glarefrom such head lamps without reducing the intensity of the illuminatingbeam of light.

By glare I mean theA side light which issues from the front glass of anordinary head lamp in a widely divergent cone and which is so annoyingand even dangerous to persons who are compelled to approach and passwithin a few feet of such a head lamp, as in automo ile driving. Most ofthis glare is direct (not reflected) light from the lamp filament,which, of course` is heated to dazzling incandescence, and I do notrefer to the glare that would be produced by the reflected beam cone oflight from a head lamp or spot-light that happens to be improperlypointed to the right or left of its proper path.. A beam of lightpowerful enough to illuminate a highway at a considerable distancemustof necessity be blinding to theunshaded eye, and the laws of manyStates take this into account and prohibit the re-` ilected beam conefrom an automobile head lam to rise more than a few feet above the roa[Even thoughl this adjustment ism-made, however, the scattered lightcone from the present type of head lamp is powerful enough to producedangerous glare, andmy invention permits the complete control of thislight so that it may be directed in any desired manner.

Referring to the drawings y Figure l is a vertical cross section of ahead light embodying my invention.

Fig. 2 is a modification in which three different treatments of 'therays are provided for.

Referring more particularly to the drawings; A, denotes an ellipticalreflectonthe elliptical surface of which is formed to reflect the lightrays to given central points in front of the reflector; F, denotes apoint at which the reflected rays would meet if iio lens wereinterimposed. X-X reprerafented oct. 11, 1921.

sents the center aXis'of the light rays and passes through the foci Land 4. B, represents a convex lens formed as shown in the drawings ofprisms arranged in circles of varylng diameter for transmitting directradiating rays in horizontal lines; 7), is a double concave lens; C,represents a non-reflecting surface or outer ring adapted to absorblight rays not otherwise provided for in my invention.

The lines G and g denote the path of di-` rect rays. The lines H, showthe path of the reflected rays. Y

In the modification shown in Fig. 2, b2 denotes a plain glass throughwhich pass direct rays, without refraction. The path of these rays isdenoted by the lines g.

A given lens can of course, only give definite direction to a group ofrays that fallv ceeding directly from the light source L,-

being transmitted by the convex lens B, being refracted thereby so thatthey emerge in a beam parallel to the axis of the reflector.

The second series of rays marked H, are

reflecteed from the reflector A. This series 4 is by far the largest.These rays would converge on the focus F; but the do'ble concave lens btransmits these rays and refracts them so that they emerge in raysparallelwto the aXis X--X of the reflector A.

The third series of rays is marked g. This series of rays comprises onlya very small proportion of the total light treated. These rays aredirect rays and pass through the double concave lens b, being refractedthereby into a widely divergent cone 9 9. This light is small in amountto begin with and as it is spread over such a wide angle it 1s renderedso feeble that it is not productive 110 of glare.

Iilig. 2, shows still another series of rays which I:have marked g;these are direct' rays and pass through a plain glass b2, Withoutchanging their direction to provide illumination of the roadimmediately7 in front of the head light.

I prefer to mold my double lens of one piece of glass, though this isnot absolutely necessary. 4

Having provided means to eiiect the practical individual treatment ofthe direct. and reflected beams, whatI Wish to claim and secure byLetters Patent are:

1. In a headlight, the combination of an ellipticalreflector, a sourceof light located substantially at the inner focus of the reflector, alens covering the mouth of the reflector and located near the outerfocus of the reflector, said lens having a central concave`portion whichreceives all the reflected rays and issues them Vin a parallel beam oflight and a plurality of arcuate concentric prisms which receive thegreater portion ot' direct rays and transmit them in a parallelcylindrical beam of light.

2. In a headlight, the combination of an elliptical reflector in whichthe outer portion of said reflector is covered with a nonreflectinocoating, a source of light located substantially at the inner focus ofthe re.- flector, a lens covering the mouth of the re- Hector andlocated near the outer focus of the reflector, said lens having acentral concave portion which receives all the reflected rays and issuesthem in a parallel beam of light and a plurality of arcuate concentricprisms which receive the greater portion ot direct rays and transmitthem in a parallel cylindrical beam of light.

3. In a headlights the combination of an elliptical reflector, a sourceof light located substantially at the inner focus of the reflector, alens covering the mouth of the reflector and located near the outerfocus ot' the reflector, said lens having a central double concaveportion which receives all the reflected rays and issues them in aparallel beam of light and also receives the central direct rays .andspreads them laterally, and a plurality ot' arcuate concentric prismsWhich receive the greater portion of direct rays and transmit them in aparallel cylindrical beam of light.

4. In a headlight, the combination of an elliptical reflector, a sourceof light located substantially at the inner focus of the reflector, alens covering the mouth of the relector and located near the outerfocus, said lens comprising a central double concaveportion, a pluralityof arcuate prisms surrounding the concave portion and covering the u perhalf of the lens, the lower portion o the lens surrounding the concaveportion being free from prisms and allowing a portion of the downwarddirect rays to pass unmodified.

n testimony that I claim the foregoing as my own, I aflix my signature.

JOHN A. RITTER.

